Inserts for current collectors



Patented Aug. 19, 1952 UNITED STATES PATENT OFFICE INSERTS FOR CURRENT COLLECTORS George A. Mead, Mansfield, Ohio, a ssignor to The Ohio. Brass Company, Mansfield, Ohio, a corporation of New Jersey No Drawing.

4 Claims. 1

My invention pertains to current collecting devices and hasparticular reference to one for collecting current from a trolley wire such as an insert for a sliding sho.e.-

Such devices should be good conductors of electricity and possess high wearing properties and which will not effect undue wear of the trolley wire.

Another object of my invention is to'produce the current collector which is a combination of a metal having a relatively high wear resisting property such as iron or steel and a metal possessing a lubricating property.

.Inserts for current collectors have been made wholly of carbonaceous material but have not been found satisfactory, having a relatively short life.

Other inserts have been made of carbon and then impregnated with a low melting point metal, such as lead, tin, zinc etc., while in a molten state as disclosed in U. S. Patent 2,169,154. This insert has proved a commercial success but it is the purpose of this invention to provide an insert which will have still further success through increase in life.

Current collectors of the shoe and insert types,

U. S. Patent 2,185,270, made wholly of copper or bronze, or of iron or steel have not been entirely satisfactory but a shoe or insert made of a wear resisting metal such as iron or steel together with a metal acting as a lubricant will be found quite satisfactory and of a relatively long life.

An insert or sliding shoe forcollecting'zcurrent from a trolley wire may be composed of granular or flaky particles of steel or iron'or other materials having relatively similar wear resisting quality and the particles held together by a relatively soft metal acting as a lubricant.

In one form of my present invention I'pro'pose alloying the iron with a softer and lower melting metal, the latter to have the lubricating properties referred to above, such metals as tin, bismuth, cadmium, lead, zinc, antimony or aluminum, the melting points of which rest between 400 degrees and 1225 degrees F., or an alloy of two or more such metals as for instance-lead 85%, antimony 13%, tin 2%. Alloys of some of the above metals will have a melting point less than 400 degrees F.

The wear resisting and lubricating metals should be uniformly distributed and one of the alloys I propose is of a mushy or pasty consistency while hot such as the dross found in the bottom of a galvanizing tank after use over a period of time.

Application January 14,1949, Serial No. 71,045

This drossis not uniform in composition since.

it depends upon the temperature of the zinc bath and amount of iron galvanized also the length of time the drosshas been forming, but it'may be said to ordinarily run around 3% to 5% of iron and the balance practically zinc.

However this dross which is a by-Droductof the galvanizing process may be brought-up to a standard desired-by raising the temperature above that which will render the dross mushy?- or pasty and then add Zinc or iron thereto such as disintegrated'iron in a powdered, flake or granular state, the higher thetemperature the more iron will enter the alloy and the harder will be the product when it cools. Atemperature of 1400 degrees F. may result in-a Zn-Fe alloy containing up to 12% iron.. r

A modification of the above is to form an alloy of zinc and iron of 3 to 5 percent iron vor use the dross as it comes from the galvanizing tank, then bring the temperature of the dross to that which will cause it to assume a pasty state referred to above and then add thereto disintegrated iron in a powdered, flake or granular state as desired and to then allow the mass to solidify in which state it will consist of a zinc iron alloyof the 3 to 5 percent iron and the balance of the mix containing the added disintegrated iron in a free state. The free iron will act as a wear resisting material and may be added to the zinc-iron alloy in such amount as to secure the wear resisting properties when.

placed in current collecting device to follow along a trolley wire, bearing in mind that the iron content is not sufiicient to bring undue wear upon the trolley wire.

It may be found of advantage to first treat the. disintegrated iron-to be added and remain in a freestate, with zinc chloride or other flux.

so the iron and zinc dross will form a strong surface union with the iron particles.

While I have referred above to the use of dross, a by-product, the Zn-iron alloy may be formed ofyirgin zinc and iron. The iron is not only harder and of a more wear resisting mate@ alloys forming the lubricating portion of the insert.

, The softer or lower melting point metals referred to above or their alloys may run from 50 to 95 percent and the free iron or other wear resisting metal from 50 to 5% respectively.

If desired, there may be added to the metals forming the mass while in a molten condition, a small quantity of powdered carbon or graphite, which will act as a lubricant as well as the softer and lower melting point metals referred to.

The wear resisting material may also consist of a very fine grade of abrasive such as used in polishing, and belonging to the silicon carbide group or to the aluminum oxides which will operate as wear resisting materials but not as current conductors.

The proportions of each and every element used to make up the composition of my improved insert should be found by trial under actual operating conditions as there are many conditions met in actual operation which cannot be reproduced in a laboratory under normal conditions and the time element is of great importance in such determination. I j

A specific embodiment of my invention consists in forming an insert for a current collector comprising a body of metal, formed of an alloy of zinc and iron in the proportion of 3% to 12% by weight of iron, which forms a pasty body while hot; the zinc and iron mixture is held at a temperature around 1400" F. until the iron is dissolved in the zinc which may take considerable time depending upon the form in which the iron is introduced. Then form a mixture by adding to the alloy while in such heated plastic condition an amount of iron in the form of powder, flakes or grains uniformly distributediin the alloy in the proportion of 5% to 50 by weight of the mix and the balance being the alloy in an amount of 95% to 50% by weight respectively. The alloy may have substituted for the zinc at least one of the several lubricating met'als'melting below 1225 F. and there may be substituted for the free iron at least one of the several wear resisting metals harder than the lubricating metal and melting above 2500 F.

To form an insert for a current collector or for other purposea die is produced with a cavity having a shape of the desired article and as soon as the mix has been prepared a quantity suflicient of any of the above described compositions is placed in the die cavity while the composition is in a pasty or soft condition below the melting point and then the composition subjected to pressure, which will depend upon the temper of the mass, the lower the temperature the greater the pressure required, but if the mass is pressed too cold it may develop cracks.

The following claims define my invention.

7 I claim: j

1. An insert for a current collector comprising a compressed metallic body composed of an alloy of zinc with 3% to 12% by weight of iron, and a 'wear resisting material in a disintegrated form in an amount between 5% and 50% by 4 weight of the body and the balance of the body being the said alloy, the said wear resisting material being metallic iron uniformly distributed throughout the alloy and retained in the alloy in its original unalloyed form.

2. An insert according to claim 1 in which the wear resisting metal is provided with a thin coat of flux prior to being incorporated into the alloy whereby the alloy will cohere with the wear resisting metal of the body.

3. An insert for a current collector comprising a compressed metallic body composed of a lubricating alloy and a harder wear resisting material in a free state, the alloy formed of at least one metal selected from the group consisting of tin, bismuth, cadmium, lead, zinc, antimony and aluminum with 3% to 12% by weight of iron, and the wear resisting metal being in a disintegrated form in an amount between 5% and 50% by weight of the body, the wear resisting metal being a metal which is harder than the alloy and uniformly distributed throughout the body and retained in thealloy in an unalloyed form therewith.

4. An insert for a current collector comprising a compressed metallic body composed of an alloy formed of at least one metal selected from the group consisting of tin, bismuth, cadmium, lead, zinc, antimony and aluminum with the addition of 3% to 12% by weight of iron dissolved therein, and a wear resisting metal in a disintegrated form, consisting at least of one metal selected from the group consisting of iron, nickel, cobalt and chromium, present in an amount between 5% and 50% by weight of the body, the wear resisting metal being uniformly. distributed in a free state throughout the mass of the body. 7

GEORGE A. MEAD.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS OTHER REFERENCES Corse: Bearing Metals and Bearings, 1930, pages 212, 213, and 283; published by Chemical Catalog Go, New York. 

1. AN INSERT FOR A CURRENT COLLECTOR COMPRISING A COMPRESSED METALLIC BODY COMPOSED OF AN ALLOY OF ZINC WITH 3% TO 12% BY WEIGHT OF IRON, AND A WEAR RESISTING MATERIAL IN A DISINTEGRATED FORM IN AN AMOUNT BETWEEN 5% AND 50% BY WEIGHT OF THE BODY AND THE BALANCE OF THE BODY BEING THE SAID ALLOY, THE SAID WEAR RESITING MATERIAL BEING METALLIC IRON UNIFORMLY DISTRIBUTED THROUGHOUT THE ALLOY AND RETAINED IN THE ALLOY IN ITS ORIGINAL UNALLOYED FORM.
 4. AN INSERT FOR A CURRENT COLLECTOR COMPRISING A COMPRESSED METALLIC BODY COMPOSED OF AN ALLOY FORMED OF AT LEAST ONE METAL SELECTED FROM THE GROUP CONSISTING OF TIN, BISMUTH, CADMIUM, LEAD, ZINC, ANTIMONY AND ALUMINUM WITH THE ADDITION OF 3% TO 12% BY WEIGHT OF IRON DISSOLVED THEREIN, AND A WEAR RESISTING METAL IN A DISINTEGRATED FORM, CONSISTING AT LEAST OF ONE METAL SELECTED FROM THE GROUP CONSISTING OF IRON, NICKEL, COBALT AND CHROMIUM PRESENT IN AN AMOUNT BETWEEN 5% AND 50% BY WEIGHT OF THE BODY, THE WEAR RESISTING METAL BEING UNIFORMLY DISTRIBUTED IN A FREE STATE THROUGHOUT THE MASS OF THE BODY. 